Rick Deckard is a bounty hunter who is about to have one bad day. Within the space of twenty-four hours, he'll have to kill six state-of-the-art androids, have an inter-galactic corporation mess with his mind, meet a metaphysical god twice, and discover an extinct animal.
Hope he had a good breakfast.
… too bad for Rick that he starts as a hot mess.
At the beginning of the novel, Rick is a self-centered kind of guy. He sees taking care of his electric sheep as a demoralizing chore—never mind how that poor sheep feels with Rick showing his control panel to all the neighbors. He also only sees how his wife's depression affects him, noting that her lack of "vitality" means she can't support him (8.89).
He also only considers the androids he's retiring in terms of financial gain. For about the first third of the book, Rick is calculating to see how he can earn enough money to buy a large animal and replace the electric sheep. He's constantly checking his Sidney's, questioning how many andys he'd have to kill to make X amount of dollars, and telling everyone they should major in STEM fields.
And the idea of "retiring" these androids doesn't bother him:
The electric animal, [Rick] pondered, could be considered a subform of the other, a kind of vastly inferior robot. Or, conversely, the android could be regarded as a highly developed, evolved version of the ersatz animal. Both viewpoints repelled him. (4.50)
So, we can see that Rick clearly lacks empathy for androids, his electric sheep, and his wife. And we know what else lacks empathy, don't we? Yep, the androids. Rick is a big ol' hypocrite. He punishes androids for lacking empathy, when he's about the least empathic meat-sack on the planet.
Isidore subtly points out the similarity between Rick and an android. Once Pris tells him about bounty hunters, Isidore pictures: "something merciless that carried a printed list and a gun, that moved machine-like through the flat bureaucratic job of killing. A thing without emotions, or even a face" (14.33). Isidore has a similar machine-like image of Baty, whom he sees with a "frame of metal, platform of pullies [sic] and circuits and batteries" (14.39).
We see further similarities between Baty and Rick in their general callousness. While Baty enjoys handing out news of people's death (14.10), Rick finds "hungry, gleeful anticipation" in the idea that he might be able to "retire" enough andys to afford an animal (8.97). In other words, the very aspects Rick uses as an excuse to hunt androids are embodied by … himself.
But any good protagonist has to reach a point of change, and Rick begins his when he meets Phil Resch and Luba Luft.
In Luba Luft, Rick sees aspects of the world he values come to life. In Phil Resch, he sees himself in a mirror, darkly. The twist (of course there's a twist) is that Luba Luft is an android while Phil Resch is human and a fellow bounty hunter. In other words, society tells him to feel the exact opposite of how he really does.
We get a big clue to his character in the bizarre fact that Rick, despite his android-cidal tendencies, is an opera lover. In a world where everything is decaying rapidly, he knows that even his beloved operas must one day fade into memory and then even beyond memory. As he notes to himself listening to a rehearsal of Mozart's The Magic Flute:
This rehearsal will end, the performance will end, the singers will die, eventually the last score of the music will be destroyed in one way or another; finally the name "Mozart" will vanish, the dust will have won. (9.4)
Being an opera lover hints that there's something going on underneath that kill kill kill exterior—something that leaves him open for change. And when Rick meets Luba Luft, he doesn't see an android but a woman who can sing opera beautifully and (unlike a lot of humans) seems to love art. Rick actually begins to feel empathy for her and even purchases her a book featuring her favorite painting in the art museum, Munch's Puberty, moments before her execution.
He sees in her a chance to keep the "dust" from claiming another part of humanity, telling Resch that he can't kill android any more: "I've had enough. She was a wonderful singer. The planet could have used her. This is insane" (12.50). For Rick, Luba Luft did not seem to be artificial life; she "seemed genuinely alive" (12.97).
Watching Resch do his job, Rick begins to question whether he wants to be someone like that. Resch's complete lack of empathy for androids even makes Rick question whether Resch is an android himself, Voigt-Kampff test or not.
After Luba's death, Rick tells Resch the difference between them:
"The way you killed Garland and then the way you killed Luba. You don't kill the way I do; you don't try to—Hell," he said. "I know what it is. You like to kill. All you need is a pretext. If you had a pretext, you'd kill me." (12.62)
What happened to the Rick who got into his hovercar hungry with anticipation for the hunt? The absolute worst thing that could happen to a killer: he's started seeing other creatures—even androids—as fully human. Once you see that, you can't unsee it.
After Rick finishes killing the remaining androids, he flies home to find that Rachael has thrown his goat off the roof. Tired and in despair, he flies to the wasteland of north Oregon—or what will be the wasteland of north Oregon after the nuclear war kills off all the hipsters. There, he thinks, "everything about me has become unnatural; I've become an unnatural self" (21.14).
Rick has moved away from the self-centered, un-empathetic guy we met at the beginning of the novel—so far away that he's alienated himself from, well, himself. As he travels a barren, rocky hill, he takes a super symbolic journey to and from death. At its conclusion, Rick believes he has merged with Mercer—and what's more empathetic than that? This fusion shows that Rick has undergone a major personality change—which we see in action in the final chapter, when Rick admits that "electric things have their lives, too."
If Rick can change that much in one bad day, what will tomorrow bring?